https://www.youtube.com/watch?v=GzamwVH3CXU
https://en.wikipedia.org/wiki/Copenhagen_Metro , https://m.dk/en/
The Copenhagen_Metro is open for service 24 hours a day.
https://en.wikipedia.org/wiki/M2_(Copenhagen_Metro)
https://en.wikipedia.org/wiki/Copenhagen_Airport#Metro
https://en.wikipedia.org/wiki/Lufthavnen_station
https://en.wikipedia.org/wiki/List_of_Copenhagen_Metro_stations
https://www.visitcopenhagen.com/copenhagen/planning/the-metro-gdk962923
https://en.wikipedia.org/wiki/Hitachi_Rail_Italy_Driverless_Metro
"The trains are 39 m (127 ft 11+3⁄8 in) long, 2.65 m (8 ft 8+3⁄8 in) wide, and weigh 52 t (51 long tons; 57 short tons). Each train consists of three articulated cars with a total of six automated, 1.6 m (5 ft 3 in) wide doors, holding up to 96 seated and 204 standing passengers (300 in total)." https://en.wikipedia.org/wiki/Copenhagen_Metro#Trains
With Selective_door_operation technology, a 3 car train could become a 5 car train without having to lengthen the stations. People would simply access & leave the train in the middle 3 cars, but not the end cars.
https://en.wikipedia.org/wiki/Selective_door_operation#International_variations
